The internal diameter of the main trunk of the portal vein of 17mm indicates widening of the portal vein, which is a manifestation of portal hypertension. Normal portal vein width is 5-10mm, when breathing, the portal vein has a certain degree of physiological changes, the range of changes usually does not exceed 1mm. if the internal diameter of the main trunk of the portal vein is greater than or equal to 13mm, then it indicates that the portal vein is widened, the widening of the portal vein may be congenital portal vein anomalies, or it may be caused by acquired portal hypertension. Congenital portal vein malformation is due to the widening of the portal vein caused by abnormal portal vein development, the cause of which is unknown and may be related to chromosomal variations. Acquired portal hypertension is common in diseases such as cirrhosis, Buerger’s syndrome, and constrictive pericarditis, which cause increased resistance of blood from the portal vein to enter the liver, leading to stagnation of blood in the portal vein and increased portal pressure. In case of abnormal portal vein test results, it is recommended to consult a doctor in time to clarify the cause of the disease with the help of a doctor and carry out targeted treatment or therapy.